1. Field of the Invention
The invention relates to a winding machine and process for winding a material web, in particular a paper or cardboard web, onto a reel, in which the material web is guided by way of a carrying drum that can be supplied with suction, and a hip formed between the carrying drum and the reel.
2. Discussion of Background Information
A winding machine of this kind has been disclosed, for example, in European Patent EP-B1-0 658 504, wherein a carrying drum is provided with internally supplied suction. A corresponding winding machine is used, for example, at the end of a machine used for producing or refining a material web. It can also be used for wrapping a winding roll that has already been completely wound. Such a machine can, for example, be a paper making machine.
In practice, problems can occur with the initial threading of the material web or a threading end or threading tip of this material web onto the winding device. Thus, until now, it has been customary to transport the threading end of the material web to the carrying drum, by way of threading ropes, blower plates, vacuum belts and/or the like, whereupon this threading end is guided around the carrying drum. Then, the threading end is removed from the carrying drum once more, by way of a doctor (scraper), e.g., a blowing doctor, a blowing wedge, or the like and by way of baffle, and is discarded into a rejects slusher. The paper web then widens out and is continuously discarded into the rejects slusher. For example, a baffle with a blower device can be provided for this purpose. Then, the material web is cut, by way of a gooseneck, band, knife, water jet, and/or the like and is threaded onto an empty reel that is provided. In this regard, an uncontrolled self-threading of the in particular strip-like threading end or the entire material web onto a provided empty reel or an already wound reel can occur. This problem occurs to a greater degree at high machine speeds and with grooved or bored carrying drums that are not supplied with suction.
In conjunction with a conventional winding machine 10, there is shown in FIG. 1 one such undesirable self-threading that deviates from the desired web path A. The web path B represents the case in which, immediately after the nip 18 formed between the carrying drum 12 and an empty reel 16', the strip-like threading end of the material web 14, that is guided by way of the carrying drum 12 or the entire material web 14 is automatically wound in an uncontrolled manner onto the empty reel 16'. The letter C represents the case in which there is an uncontrolled self-threading onto an already wound reel 16. In contrast, in the desired web path A, the threading end or the material web 14 is first detached from the carrying drum 12 by a doctor 20 and is discarded into the rejects slusher 22.
With a carrying drum that is supplied with suction, the guidance of the threading end, which is generally strip-like, or the material web is influenced all the way to the exit region at the doctor 20 so that in this instance, a self-threading onto the still empty reel 16' (instance B) can be prevented. Carrying drums are used for this purpose, that are connected to a vacuum source and are supplied with suction by one or both pins. In the frequently used drum embodiments, the inner chamber is supplied with suction without built-in elements. As a result, however, secondary air can now penetrate into the part of the carrying drum that is not wrapped around, which results in a relatively high energy consumption. Carrying drums with internal sealing have, among other things, the disadvantage that functional elements are disposed inside the carrying drum. The carrying drum must be removed, for example, in the event of a possible change of seals. All of the known embodiments have the disadvantage that a doctor device is also always required in order to remove the threading end or the paper web from the carrying drum.